In recent years, there is an increasing demand for big data analysis. It is desirable to collect as many data samples as possible in order to obtain more accurate and more useful analysis results in big data analysis.
The government of Japan has a plan to carry out policy to promote big data analysis in the domestic medical field in the future. This plan aims at a situation where pieces of data of electronic medical records are collected from hospitals, the collected pieces of data are processed to anonymous data, and groups that wish to use the anonymous data are provided with the data as data available for big data analysis.
An electronic medical record is data including much personal information that is related to privacy of patients. Thus, it is desirable that a measure be taken to prevent leaks of personal information when a great amount of this kind of data is collected.
Various techniques that collect and utilize pieces of medial data such as electronic medical records are also known (see for example Patent Documents 1 through 5).
Patent Document 1: Japanese Laid-open Patent Publication No. 2010-128718
Patent Document 2: Japanese Laid-open Patent Publication No. 2004-287774
Patent Document 3: Japanese Laid-open Patent Publication No. 2009-15835
Patent Document 4: Japanese National Publication of International Patent Application No. 2013-537326
Patent Document 5: Japanese Laid-open Patent Publication No. 2009-266077